Scientists have developed a crude form of telepathy in animals by enabling a pair of rats to pass instructions using only their mind.

Using microchips implanted in their brains to communicate, the rats were able to collaborate and solve simple puzzles, even though in one experiment they were thousands of miles apart.

Researchers claim this is the first example of a 'brain-to-brain interface', raising the prospect that one day animals - and humans - could be able to read each other's minds.

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Researchers electronically tied the brains of two rats, one in the U.S (right) and another in Brazil (left), allowing them to solve problems together

The rats were connected to each other via a special interface which plugged directly into their brain

The team from Duke University in
North Carolina said: 'As far as we can tell, these findings demonstrate
for the first time that a direct channel for behavioural information
exchange can be established between two animals' brains without the use
of the animal's regular forms of communication.'

Lead researcher, Miguel
Nicolelis, a pioneer of research into brain-computer interfaces, said
the study was the first step towards the linking of multiple minds to
form an 'organic computer' or 'brain-net' that would allow sharing of
information among groups of animals.

'We cannot even predict what kinds of
emergent properties would appear when animals begin interacting as part
of a brain-net,' he said.

'In theory, you could imagine that a
combination of brains could provide solutions that individual brains
cannot achieve by themselves.'

He said it could even lead to one animal
incorporating another's sense of 'self', although there are fears it
could result in the development of mind control.

In the experiments, published in the
journal Scientific Reports, microscopic electrodes implanted into the
rats' brains enabled one animal to pass on instructions to the other,
even though it was in a separate cage.

The first rat, known as the
'encoder', was taught to find water in its cage by responding to a light
and pressing a particular lever.

Its brain was connected to a second
animal, known as the 'decoder', which was not given the light signals.

Instead, the second animal relied
solely on the brain instructions, but when stimulated still pressed the
right lever to receive a reward 70 per cent of the time - far more often
than it would have by chance, demonstrating they had been guided by the
other rat's mind.

A still from a video released by Nicolelis Laboratory explaining the logistics of the experiment

Remarkably, the communication between
the rats seemed to be two-way.

The encoder rat did not receive a full
reward if the decoder made a wrong choice, and as a result, became more
decisive and generated clearer brain signals.

'We saw that when the decoder rat
committed an error, the encoder basically changed both its brain
function and behaviour to make it easier for its partner to get it
right,' said Dr Nicolelis, who claimed this suggested a 'behavioral
collaboration' between the pair of rats.

Duke University Medical Center neurobiologist Miguel Nicolelis led the study, published in Scientific Reports

A second test involved pairs of rats
distinguishing between narrow and wide openings using their whiskers.

Again, signals transmitted from one rat helped the other take the
right action to obtain a reward.

Evidence from this study suggested
that the decoder rat began to develop a double identity, by picking up
sensations from two sets of whiskers - its own and those of its partner.

'Our studies of the sensory cortex of
the decoder rats in these experiments showed that the decoder's brain
began to represent in its tactile cortex not only its own whiskers, but
the encoder rat's whiskers, too,' said Dr Nicolelis.

HOW THEY DID IT

Microscopic electrodes implanted into the
rats' brains enabled one animal to pass on instructions to the other,
even though it was in a separate cage.

The first rat, known as the
'encoder', was taught to find water in its cage by responding to a light
and pressing a particular lever.

Its brain was connected to a second
animal, known as the 'decoder', which was not given the light signals.

Instead, the second animal relied
solely on the brain instructions, but when stimulated still pressed the
right lever to receive a reward 70 per cent of the time - far more often
than it would have by chance, demonstrating they had been guided by the
other rat's mind.

'We detected
cortical neurons that responded to both sets of whiskers.'

This
experiment was repeated with another pair of rats, one in the US city of
Durham, North Carolina, the other in Natal, Brazil.

By recording brain signals from one
rat and transmitting them over the internet to the other, scientists
were able to alter the second rodent's behaviour despite the vast
distance.

British expert Professor Christopher
James, from the University of Warwick, who has conducted similar
research, said: 'We are far from a scenario of well-networked rats
around the world uniting to take us over, the stimulation is crude and
specific.

'As for the ethics, I struggle to think of any applications
that would not have ethical issues.'